Martian Invasion

Probing lively puzzles on the Red Planet

Just 2 months ago, Mars loomed high in the sky, its ruddy countenance so close that anyone with a backyard telescope could make out the planet’s white south-polar cap and a central smudge known as Syrtis Major. Not in 60,000 years had Mars and Earth been so close, and they won’t be again for another 2 centuries.